COMPOUND SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME

• US 20120220089A1
• Filed: 12/14/2011
• Published: 08/30/2012
• Est. Priority Date: 02/25/2011
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: IMADA, Tadahiro, Kikkawa, Toshihide
• Granted Patent: US 8,765,554 B2
• Time in Patent Office: Days
• US Class Current: 438/270
• CPC Class Codes: H01L 2224/0603 Bonding areas having different sizes, e.g. different heights or widths
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48472 the other connecting portion not on the bonding area also being a wedge bond, i.e. wedge-to-wedge
• CPC Class Codes: H01L 29/0619 with a supplementary region doped oppositely to or in rectifying contact with the semiconductor containing or contacting region, e.g. guard rings with PN or Schottky junction
• CPC Class Codes: H01L 29/2003 Nitride compounds
• CPC Class Codes: H01L 29/205 in different semiconductor regions , e.g. heterojunctions
• CPC Class Codes: H01L 29/4236 within a trench, e.g. trench gate electrode, groove gate electrode
• CPC Class Codes: H01L 29/66462 with a heterojunction interface channel or gate, e.g. HFET, HIGFET, SISFET, HJFET, HEMT
• CPC Class Codes: H01L 29/7787 with wide bandgap charge-carrier supplying layer, e.g. direct single heterostructure MODFET
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H03F 1/3247 using feedback acting on predistortion circuits H03F1/3264 takes precedence
• CPC Class Codes: H03F 1/523 for amplifiers using field-effect devices H03F1/526 takes precedence
• CPC Class Codes: H03F 2200/204 A hybrid coupler being used at the output of an amplifier circuit
• CPC Class Codes: H03F 2200/426 the amplifier comprising circuitry for protection against overload
• CPC Class Codes: H03F 2200/444 Diode used as protection means in an amplifier, e.g. as a limiter or as a switch
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 3/189 High-frequency amplifiers, e.g. radio frequency amplifiers
• CPC Class Codes: H03F 3/24 of transmitter output stages

Abstract

A gate electrode is formed so as to embed an electrode material in a recess for an electrode, which has been formed in a structure of stacked compound semiconductors, through a gate insulation film, and also a field plate electrode that comes in Schottky contact with the structure of the stacked compound semiconductors is formed by embedding an electrode material in a recess for an electrode, which has been formed in the structure of the stacked compound semiconductors so that the field plate electrode directly comes in contact with the structure of the stacked compound semiconductors at least on the bottom face of the recess for the electrode.

Claims

1. A compound semiconductor device comprising:

a structure of stacked compound semiconductors, in which a first recess and a second recess are formed;

a gate electrode formed in the first recess through a gate insulation film; and

a field plate electrode which is formed in the second recess and comes in Schottky contact with the structure of the stacked compound semiconductors.

2. The compound semiconductor device according to claim 1, wherein the second recess is formed so as to be shallower than the first recess.

3. The compound semiconductor device according to claim 1, wherein

the structure of the stacked compound semiconductors has a cap layer on the top layer, and

the second recess is formed only in the cap layer.

4. The compound semiconductor device according to claim 3, wherein

the cap layer is formed of a first layer, a second layer and a third layer which are sequentially stacked,

the first layer and the third layer have a narrower band gap than that of a compound semiconductor layer under the cap layer in the structure of the stacked compound semiconductors, and the second layer has a wider band gap than that of the compound semiconductor layer.

5. The compound semiconductor device according to claim 4, wherein the second recess is formed so that the second layer is exposed to the outside at the bottom face.

6. The compound semiconductor device according to claim 1, further comprising:

a source electrode and a drain electrode formed on the structure of the stacked compound semiconductors so as to be adjacent to the gate electrode, wherein

the field plate electrode is electrically connected with the source electrode.

7. A method for manufacturing a compound semiconductor device comprising:

forming a first recess in a surface layer in a structure of stacked compound semiconductors;

forming a gate insulation film in the first recess;

forming a second recess in a surface layer of the structure of the stacked compound semiconductors;

forming a gate electrode in the first recess through the gate insulation film; and

forming a field plate electrode which comes in Schottky contact with the structure of the stacked compound semiconductors in the second recess.

8. The method for manufacturing the compound semiconductor device according to claim 7, wherein the second recess is formed so as to be shallower than the first recess.

9. The method for manufacturing the compound semiconductor device according to claim 7, wherein the gate electrode and the field plate electrode are formed in the same step.

10. The method for manufacturing the compound semiconductor device according to claim 7, wherein

the structure of the stacked compound semiconductors has a cap layer on the top layer, and

the second recess is formed only in the cap layer.

11. The method for manufacturing the compound semiconductor device according to claim 10, wherein

the cap layer is formed of a first layer, a second layer and a third layer which are sequentially stacked,

the first layer and the third layer have a narrower band gap than that of a compound semiconductor layer under the cap layer in the structure of the stacked compound semiconductors, and the second layer has a wider band gap than that of the compound semiconductor layer.

12. The method for manufacturing the compound semiconductor device according to claim 11, wherein the second recess is formed so that the second layer is exposed to the outside at the bottom face.

13. The method for manufacturing the compound semiconductor device according to claim 7, further comprising:

forming a source electrode and a drain electrode on the structure of the stacked compound semiconductors so as to be adjacent to the gate electrode; and

electrically connecting the field plate electrode with the source electrode.

14. A power-supply unit comprising:

a transformer, and a high-voltage circuit and a low-voltage circuit which sandwich the transformer,

the high-voltage circuit comprising a transistor,

the transistor comprising;

a structure of stacked compound semiconductors, in which a first recess and a second recess are formed;

a gate electrode formed in the first recess through a gate insulation film; and

a field plate electrode which is formed in the second recess and comes in Schottky contact with the structure of the stacked compound semiconductors.

15. The power-supply unit according to claim 14, wherein

the high-voltage circuit comprises a PFC circuit, and

a first switching element provided in the PFC circuit is the transistor.

16. The power-supply unit according to claim 15, wherein

the high-voltage circuit further comprises an inverter circuit connected to the PFC circuit, and

a second switching element provided in the inverter circuit is the transistor.

17. The power-supply unit according to claim 14, wherein the transistor has the second recess which is formed so as to be shallower than the first recess.

18. A high-frequency amplifier for amplifying input high-frequency voltage and outputting the amplified high-frequency voltage,

the high-frequency amplifier comprising a transistor,

the transistor comprising:

a structure of stacked compound semiconductors, in which a first recess and a second recess are formed;

a gate electrode formed in the first recess through a gate insulation film; and

a field plate electrode which is formed in the second recess and comes in Schottky contact with the structure of the stacked compound semiconductors.